SquirrelJME/SquirrelJME

#!/bin/sh
# ---------------------------------------------------------------------------
# Multi-Phasic Applications: SquirrelJME
#     Copyright (C) Stephanie Gawroriski <xer@multiphasicapps.net>
#     Copyright (C) Multi-Phasic Applications <multiphasicapps.net>
# ---------------------------------------------------------------------------
# SquirrelJME is under the GNU General Public License v3+, or later.
# See license.mkd for licensing and copyright information.
# ---------------------------------------------------------------------------
# DESCRIPTION: Calculates the relative path from one target to another

# Force C locale
export LC_ALL=C

# Directory of this script
__exedir="$(dirname -- "$0")"

# No base specified, just a target
if [ "$#" -eq "1" ]
then
    __base="$(pwd)"
    __targ="$1"

# Base and target specified
elif [ "$#" -gt "1" ]
then
    __base="$1"
    __targ="$2"

# Bad command call
else
    echo "Usage: $0 [target]" 1>&2
    echo "       $0 [base] [target]" 1>&2
    exit 1
fi

# Make absolute
__base="$("$__exedir/absolute.sh" "$__base")"
__targ="$("$__exedir/absolute.sh" "$__targ")"

# Keep going up to skip the parts of the path which are exactly the same
__i=2
while true
do
    # Extract both components    
    __a="$(echo "$__base" | cut -d '/' -f "$__i")"
    __b="$(echo "$__targ" | cut -d '/' -f "$__i")"
    
    if [ "$__a" != "$__b" ]
    then
        break
    fi
    
    __i="$(($__i + 1))"
done

# Go up the base directory and make dots for every path element
__j="$__i"
while true
do
    __a="$(echo "$__base" | cut -d '/' -f "$__j")"
    __j="$(($__j + 1))"
    
    # Nothing left to add
    if [ -z "$__a" ]
    then
        break;
    fi
    
    # Add slash
    printf '%s' "../"
done

# Append elements on the second set from the base to the result
__j="$__i"
while true
do
    __b="$(echo "$__targ" | cut -d '/' -f "$__j")"
    __j="$(($__j + 1))"
    
    # Nothing left to add
    if [ -z "$__b" ]
    then
        break
    fi
    
    # Add that element
    printf '%s' "$__b"
    
    # If this is not the last element, add the slash
    __zb="$(echo "$__targ" | cut -d '/' -f "$__j")"
    if ! [ -z "$__zb" ]
    then
        printf '%s' "/"
    fi
done

# Ending newline
echo